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Discussion Starter · #1 ·
how much horse power is gained when u are totally catless?
 

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ebr0t said:
a search would help

tbe is normally said to be around 20 wheel
uppipe normally around 10 wheel
so 30 hp to wheel rougly
 

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the key is in the tuning... throwing that stuff on a stock WRX with no way to tune it, performance gains might be the opposite in that of performance decreases.


-mike
 

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MJU1983 said:
throwing that stuff on a stock WRX with no way to tune it, performance gains might be the opposite in that of performance decreases.
you mean taking that "stuff" off? Removing cats and opening up your exhaust will only help you in the HP department- especially with a turbocharged car... Do you have any data showing a larger, more free-flowing exhaust has actually hurt the wrx's performance? If so, I would love to see it...

I agree that tuning is important. Usually a decent tune will help you by increase your power, however, it is not a necessity for just an exhaust upgrade. I think ebort gave a good estimate of around 30hp increase...

for example, this is a dyno from the TXS website:
 

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sdwrx said:
you mean taking that "stuff" off? Removing cats and opening up your exhaust will only help you in the HP department- especially with a turbocharged car... Do you have any data showing a larger, more free-flowing exhaust has actually hurt the wrx's performance? If so, I would love to see it...

Usually a decent tune will help you by increase your power, however, it is not a necessity for just an exhaust upgrade.
If you run your car without cats and no way to tune it, performance is not going to increase no. Thats just thinking logically. Ill find you some more info too.

-mike
 

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sdwrx said:
I'd like to hear the logic behind this one... :screwy:
Its about tuning. The stock computer is set up to perform the way the car sits. When its catless, would it make sense that the stock computer is still tuned for what you have now? Or what you did have? 3 cats?

Whats so hard to understand that if you put say a turboXS stage 2 on your car and no UTEC... that your performance gains would be the same? I'd say they would be half of that of the gains with the mods and a utec.

-mike

simple answer: Catless and no way tune = gains minimal if any. Catless and a way to tune= gain.
 

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The stock computer is set up tons rich in my experience. Opening the exhaust will lean that out a bit and result in gains. Much like an intake that gains 9HP on a otherwise stock WRX. Getting and EMS of some sort will help a ton on top of that!
 

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MJU1983 said:
Its about tuning. The stock computer is set up to perform the way the car sits. When its catless, would it make sense that the stock computer is still tuned for what you have now? Or what you did have? 3 cats?
the stock ecu does have some adjustability and can compensate for some minor upgrades such as an exhaust system.

MJU1983 said:
Whats so hard to understand that if you put say a turboXS stage 2 on your car and no UTEC...
did you not see the graphs I posted above?


MJU1983 said:
simple answer: Catless and no way tune = gains minimal if any.
Mike, I think it's time to look for another job........ :rolleyes:

BTW, I would still like to see your "proof" that a catless exhaust system decreases performance on an otherwise stock wrx.
 

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MJU1983 said:
If you run your car without cats and no way to tune it, performance is not going to increase no. Thats just thinking logically. Ill find you some more info too.

-mike
:confused1 :confused1 :confused1 :confused1



you've completely lost it, man.

holy crap. :eek3:
 

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Mike your freaking me out man:confused1 you should know better.... Point intact: Remember about 5 months ago when Ron did his first offical "dyno night" with his new awd dyno. I was there along with scrapy2. My car, if you remember, is completely catless with godspeed dp, autospeed up and borla cat back as the only mods, no aftermarket boost or fuel control. I ended up putting down 217 at the wheels which is about 255ish crank hp I beleive. You where there and should of seen it with your own eyes. At that point in time though you may have not know I had no engine management...I hope;)
 

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The graph

Btw, If anyone can give me any more interesting info from this dyno sheet that would be cool. I'm a dyno chart noob:wiggles:
 

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sdwrx said:
Mike, I think it's time to look for another job........ :rolleyes:

BTW, I would still like to see your "proof" that a catless exhaust system decreases performance on an otherwise stock wrx.
Thanks for the tip, ill be sure to get a new job ASAP.

and, it has been years since this was an issue... Back in the days of the unichip. Without tuning the gains are no where near what they could be. That is all I am saying. So you can take your little rollseyes smiley and keep it.

-mike
 

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i think what mike is trying to say is that if you go completley catless on a stock car your HP gains will be minimal to the gains you can have with the same car that you can tune. the stock wrx has o2 sensors. when they strart to realise that the fuel is not being purnet up at all (cat does most that work) it will start to lean your car out. messing up the fuel/air mixture. i think thats what mike is trying to say
 

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sdwrx said:
the stock ecu does have some adjustability and can compensate for some minor upgrades such as an exhaust system.



did you not see the graphs I posted above?




Mike, I think it's time to look for another job........ :rolleyes:

BTW, I would still like to see your "proof" that a catless exhaust system decreases performance on an otherwise stock wrx.
look at your profile.... see the hp you have on your car? now add about 140WHP to your car and you have what milkes car made. also you could take about 2 seconds off your 1/4 time and you would have what mike had. now i suggest mr 62post stock car buddy that you keep your personal remarks to yourself. Thanks
 
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